Mutually Exclusive
by Quicksliver
Summary: Sherlock gets jealous, and John takes the opportunity to force a pressing issue.


**Title:** Mutually Exclusive  
><strong>Rating:<strong> PG-13  
><strong>Warnings:<strong> Slash, M/M kissing  
><strong>Characters:<strong> John Watson, Sherlock Holmes, Greg Lestrade  
><strong>Pairings:<strong> John/Sherlock, established. Also mentions of Sherlock/Unnamed OCs  
><strong>Notes:<strong> I don't like this one very much, but I think it's as good as it's gonna get, so… Giant thank you to Jademac2442 and tawg, who made it readable. I was writing this as a present to Liz, but no. It's not good enough for my liz.  
><strong>Disclaimer:<strong> Sherlock, John, all of their friends and the many places the visit do not belong to me. If they did, I wouldn't have to write fanfiction, now would I?  
><strong>Summary:<strong> Sherlock gets jealous, and John takes the opportunity to force a pressing issue.

* * *

><p>John had thought that today would be a good day, honestly. Sherlock had spent most of the morning quietly doing an experiment in the kitchen, fiddling in silence with a bright blue liquid and a microscope, so John and time to finish nearly all of his paper without interruption. Then Sherlock's phone had piped, and he'd excitedly announced that Lestrade had a case for them while pulling on his coat and gloves. John struggled into his own jacket on the way down the stairs, grinning a little while Sherlock flagged down a cab. The game was on, was it not?<p>

They'd gone, riding in the cab wordlessly, and John had watched Sherlock stare out the window with bright eyes. He had wondered how many things Sherlock noticed from the quick flashes outside that other people would miss, or if Sherlock took the time they spent in cabs to relax and take a breath. Probably not.

He'd absently set his hand on Sherlock's knee, which had drawn the detective's attention for a moment and earned him a tiny, warm smile. Random displays of affection were usually frowned upon, but John had found this one action in particular always managed to coax a smile out of Sherlock.

Lestrade had met them at a pretty little suburban house with a green garage door and perfectly landscaped lawn, which was bustling with police officers looking for evidence. The older detective lifted the police tape and led them inside.

The victim lay sprawled on the floor of her foyer, eyes shut, wearing only a green nightgown with pink cartoon elephants on it. She had been about thirty, with pretty brown hair and sharp, bird like features.

"Melanie Cain," Lestrade said quietly. "Found this morning by her best friend Damian Lyttle, a hair dresser at the salon she worked at. Came by to pick her up for carpool, claims her door was left open."

"Not the killer." Sherlock had muttered, staring intensely at the body. "John?"

John had stooped and examined her eyes, pointed at the bruises around her throat and said simply "Strangled by hand. Asphyxiation."

The case had been fairly easy for Sherlock to solve after that, but he still seemed excited the whole time. Lestrade and John had chatted quietly as they watched him bustle around the young woman's body with his usual grace.

However, when Sherlock had finally announced the killer had been a left-handed woman with a rather nasty cold, and that they should look closely at the Melanie's love life, because signs pointed to an old girlfriend, it had been a little less enthusiastic then usual. The cocky tinge had still been there (obviously), but he seemed less proud of himself then normal.

The cab ride home was when John had first noticed something was seriously wrong. Instead of staring out the window they way he usually did, Sherlock just fixed his eyes on the back of the cabbie's head and glared.

John hadn't risked putting his hand anywhere near Sherlock this time, the deadly look on his face was enough to convince the blogger that it was a bad idea.

When they got back to 221B Sherlock had practically flung himself out of the cab, and slammed the door before John was even aware of what was going on. He had handed the cabbie the fare with a murmur of thanks and followed.

Sherlock was back in his spot at the microscope. John stood awkwardly nearby, not removing his coat, just staring at the detective.

"Are you alright?" He asked, brow furrowed.

"Fine." Was the sharp response.

"You sure, 'cause—"

"—I said fine." Sherlock let a drop of a pale green, rather thick looking fluid hit the surface of the blue one from earlier, and it fizzed. He scribbled something down in a notebook. John continued to stare at him. "Stop thinking. It's distracting."

John huffed. He tossed his coat on the couch and flicked the telly on to see if there was anything decent playing, but ended up settling on yet another paternity-test programme because he knew they were usually the ones that coaxed his flatmate over to see.

Three hours passed. Four men weren't the father and thirteen of them were (the three episodes seemed to blend into one), and Sherlock hadn't come over to sit in his chair with his knees drawn up to his chest and his chin sitting in one palm. He also hadn't scribbled anything down in a long while, but still stared through the microscope.

Finally, John shut the telly off and stormed over to Sherlock. When John tapped his flatmate on one thin shoulder the detective finally looked at him.

Hurt. That's what swam behind the detective's light blue eyes. John's stern expression faded almost immediately. "Sherlock, what's wrong?"

"You agreed." The hurt disappeared, replaced with cool indifference. "It matters very little."

"I agreed to what?" John blinked, crossing his arms. "I don't know what—"

Oh. _Oh_.

"Is this about my conversation with Greg?" John started warily. Sherlock flicked his eyes to the floor, which was as close to a 'yes' as John was going to get. "You're upset I agreed to the date."

"Don't be ridiculous. I made it quite clear when we started our relationship that I did not expect us to be mutually exclusive." Sherlock stood and brushed past John, heading to the window. He stood there and stared outside for a few moments, watching the dark street below with a frown while John collected his thoughts.

"Greg wanted to set me up with a friend of his wife's," John said softly. "I said yes, so you're… What? Jealous?" The idea appealed to John. The great Sherlock Holmes, Jealous that he might have an interest in someone else?

"Of course not." Sherlock snapped. John walked a bit closer. "I don't get _jealous_."

"Right. That's why you're sulking instead of talking to me." John muttered.

"I do not _sulk_."

"Sure you don't." He was close enough to touch Sherlock, now, but he decided that this was all a matter of timing. "So what do you call this, hmmm?"

"I'm thinking." The detective's voice was soft.

"Mmmm." John decided this was his moment. He turned Sherlock towards him and pressed his lips against the detective's own, hand tangling in the dark curls.

Sherlock didn't budge for a moment, stubborn as always, but when John jerked their bodies together and slipped his other hand under the consultant's shirt to the small of his back it seemed to loosen him. Their lips began to move against one another, slowly at first and then with a more intense, bruising force, until John had to pull back for a breath.

"Sherlock." He muttered. His voice was low and husky. "Do you want to be 'mutually exclusive'?"

Sherlock made a little strangled noise, and John grinned. "If you want me to be only yours…" He let go of Sherlock completely now, and shrugged before turning and striding to his room "You've got to ask."

* * *

><p>He didn't open his eyes, but he did roll over in the bed so he was facing in Sherlock's direction. How long the curly haired man had been standing there was a mystery, but it was pretty early in the morning, John usually woke up around six on his own, but this time he had been roused by a creak from his doorway.<p>

"What is it, Sherlock?" He whispered, trying to wake up enough to be coherent. It had been two days since Sherlock had said a word to him, or done anything besides stare at him like he was a strangely volatile animal that might snap at any moment.

"If I were to say yes." The detective murmured into the darkness, and John had to fight back a smile. "What would your response be?"

"I don't know. Are you saying yes?"

"No."

"Then I can't help you." John buried his face in his pillow, hiding his smirk.

"Are you implying the answer you choose is conditional, and based whether or not I ask?" Sherlock sounded confused. "That's ridiculous."

"I'm saying that I won't know what my answer is until you ask, not that my answer is conditional." John smirked wider.

"Surely you have a notion of what you'd say."

"Nope."

Sherlock made sure to slam the door on his way out. John made sure to hold in his giggles for a few minutes.

* * *

><p>"Our relationship would be detrimental."<p>

John didn't look up, choosing instead to continue staring at his paper as if he hadn't heard. It'd been another two days of silence in the flat since Sherlock's early-morning visit, except this time Sherlock didn't even spare him a glance on a day-to-day basis. He just stared at the floor or the ceiling or a book shoved in front of his face as if it required all of his attention. John had given up trying to start conversation after about six hours of being completely ignored.

So when Sherlock spoke John didn't reply, aware of how fleeting the conversation could be.

"In my thirty-four years of existence I've participated in three sexual experiences which do not include you, and zero romantic relationships. I have inadvertently crushed the romantic interests of three people. My mannerisms and lack of experience in this area are not conducive to a proper emotional relationship, which is why I insisted we remain 'free agents' when we began this…" He hesitated, but John still refused to look up. "...Experience."

"…Mmmm."

"Asking you enter into a typical relationship with me would be unfair to us both."

John folded his paper and stood, cracking his spine with a soft groan. "Are you trying to convince me, or yourself?"

Sherlock didn't answer.

* * *

><p>"Alright. That's enough," John snapped. "I've had it. Why do you keep staring at me like that?"<p>

Sherlock didn't reply, just tilted his head ever so slightly. They were sitting across from one another in their respective chairs, John was typing up the latest case and Sherlock was watching silently. The silence didn't bother John, but the bloody staring was getting downright ridiculous.

"Yes. Like that. You've been doing it since last night." John hissed. "If you've got a something to say, just say it."

Sherlock's eyes flashed. "How was your date last night?"

"She was lovely." John muttered, going back to his laptop. If that was all then he could finish his post up, have a cuppa and go to bed.

"Yet you aren't interested." Sherlock was prying again. John grunted. "If you were, you'd have made a second date. You didn't."

"No." John's tone was short. His patience, already thin to start with, was being worn away bit by bit.

"Why?"

John rolled his eyes. "Because I'm not. She wasn't my type."

"What is your 'type'?"

John skipped the cuppa and just went to bed. He could drink two in the morning.

* * *

><p>When it finally came it was not all at all in the situation John had expected.<p>

They were at Bart's, and Sherlock was breaking apart a clump of mud with a tiny hammer, separating it into equal samples to put tested individually for different components. John was resting his forehead on one of the long, clean tables, eyes shut. He figured he could get an hour or so of sleep before he had to go downstairs for his shift, as long as he didn't think about anything and focused on the soft whirring of Sherlock's experiments.

"Yes." Sherlock sounded incredibly mild, as if he were commenting on the weather.

John tried to think about what Sherlock had been muttering earlier, to see if his tirade had ended in a question. The detective did that sometimes, answered his own questions hours later as if the mental conversation had never stopped.

When nothing immediately came to mind, John sighed and raised his head a fraction. "What?"

"Yes." The detective repeated.

"Yes what?"

"Yes, I would…" The slightest of hesitations made John look up all the way, to see that Sherlock had torn his eyes from the samples and was staring at the blogger. "…I would like you to be 'mine', as it were."

"…Is that so?" John blinked.

"Yes. I feel I may be able to follow the typical relationship structure with the right person. I'd like to attempt mutual exclusivity with you." Sherlock bit his bottom lip, something he'd done a few times before and one of the many things John found undeniably adorable. The slightest hint of vulnerability that showed the detective was human. "If you're receptive to the idea, of course."

John grinned. "Can't you figure it out yourself if I am?"

"I don't like to assume when it comes to social intricacies."

"Yes, Sherlock," John put his head back on the table and shut his eyes with a soft smile. "I'm receptive."

"Good."

The soft sound of Sherlock's voice muttering calculations lulled John to sleep.


End file.
